The prior mower art is aware of greensmowers useful in mowing golf course greens which require exacting mowing results to assure that the grass is even in its cut throughout the extent across the green. Some of those mowers are walk-behind mowers and some are riding mowers. Of course, the riders are inherently heavier than the walk-behind and they therefore tend to create undesirable impressions in the green, and they have other disadvantages.
Greensmowers generally employ a reel-type mower, and some of them are concerned about the clip-rate of the mowing, and that determines the quality of the mowed grass. The term clip-rate means the distance between the locations of the individual sequential grass cuts produced by the rotating cutting blades successively moving over the grass. The grass between the locations of the cuts will necessarily be left taller than the cut grass at the cut locations. So the cut rate is vital to producing an optimum condition of the grass on the golf course green.
It is also important that the greensmower be quiet in operation and light in weight and that it permit the operator to see the results of the mowing while the grass is being mowed. Further, the ultimate greensmower will be a walk-behind mower which is battery powered and has electrical circuitry which preludes mower overloads and consequent mower damage; gives the operator current information on the quantity of the battery charge; automatically and manually shuts off under both desirable and undesirable conditions; automatically shuts off the electric power by a predetermined time after the mower has been used for mowing; has both operator-presence handle-located control and electric switch control for the mower power; the motors for the mower and the traction drive automatically stop upon sensing a predetermined heat level within them; and there is the ability to adjust the pressure exerted on the ground by the reel mower roller.
It is an object of this invention to provide a mower and a method which achieve the aforementioned desirable results. Some of the features that produce those results include the fact that the mower is battery-powered for convenience and quiet operation on the golf course; there is a walk-behind mower for light weight and maneuverability on the greens; there is a greens roller for desired rolling of the green in conjunction with the mowing; there is a counterbalancing of the mower in its end-to-end dimension; there is an adjustable support for the battery so that its weight can be desirably applied relative to the ground rollers of the reel mower itself; and there is a battery box containing a plurality of batteries for providing optimum electric power and for lifting the box with the batteries for servicing, such as replacing and charging.
Particularly, this invention provides the apparatus and method for establishing the selectable clip-rate desirable for the green being mowed. In achieving this objective, the operator does not need to adjust nor control more than only one variable, namely only the mower ground speed. However, in another embodiment, both the traction speed and the reel speed are controllable by the operator at the handle location and during cutting operation.
This invention also provides for the arrangement of the support of the battery, actually in a pack of several batteries disposed in a box, and having the box selectively movable relative to the remainder of the mower and thereby control the pressure the mower rollers exert on the ground. In this arrangement, skilled greensmower operators can arrange for their own selectable ground pressure, and they can make their selections at the mowing sites.
This invention also provides the apparatus and method to both manually and automatically control the electric power in driving both the traction member and the cutting reel. Therefore, there is an avoidance of overload on the mower. Also, there is an electric signal which indicates the level of electric power available for powering the mower, so the operator can then respond accordingly, such as by changing or charging the battery even before the battery is dead.
Also, there is an electrical control system that will shut down the power to the reel motor when the battery voltage drops below a predetermined level of voltage. Even before that, there is an electric signal that indicates to the operator that the battery power is low. However, the system will still allow the use of the traction drive, so the operator can then transport the mower to a desired parking destination, but the operator will not be able to cut grass to a time when the battery is completely discharged and thereby damaged. This feature prevents abusive deep discharge of the battery, thereby avoiding harm to the battery.
The electrical system employed herein includes provision for a manual main switch control for the entire system, and it includes a manual switch for the reel motor which can be driven at a constant speed. There is an electrical variable resistor, such as a potentiometer, connected with the traction motor, and the resistor is controllable by the operator at the mower handle location, so the operator has the selectivity of the desired ground speed for the mower and for his walking speed. With the reel switch, the power to the reel can be shut off and the system can be operated under traction drive only, and thereby the system can be used only as a lawn roller.
In the event of overload on either the traction motor or the reel motor, those motors will automatically shut down. This feature is achieved by a sensor that senses a predetermined level of heat in the motors. Also, in the event that the operator leaves the mower with the two motors turned off but with the main switch key still on, the system will automatically turn itself off after a predetermined time delay and thereby avoid any danger, battery drain, or abuse of the mower.